Just to ease my curiousity......could someone post a pic of how they wire 2 batteries and also were/what they ran the 1 wire off the alternator too? Of course I am making reference to trunk mounted batteries. Thanks, John.
Pardon me for barging in, but, why do you want to use 2-batteries? As a hot-rod friend of mine always says when referring to extra parts, "If you can't throw it a 1/4 mile, you don't need it." fwiw: I think a simple parallel setup is what you'd want ("+" to "+", "-" to "-") and run a 10 gage wire from the alternator to either of the "+" terminals. I assume you have an emergency shut-off switch (or lever) at the rear (required at most tracks when you have trunk-mounted batteries)? ref: bling-bling dual terminals < -- subscribing to thread
Make sure you use an isolator. If you have 2 batteries in parallel and one of them goes bad it will draw the voltage down. The isolator prevents this from happening. 2 Batteries in parallel will deliver higher amperage (this is what you want) 2 Batteries in series will deliver higher voltage Check out Painless Performance they have some neat dual battery kits also. http://painlessperformance.com/catalogframe.htm Look under battery accessories
I have heard of guys using 2 6 volt batteries instead of 12 v batteries. You can get more cranking time/amperage that way. Just thought I'd throw that in there..haven't done it myself so I cant say how well it works
rick, one of the reasons i use 2 batteries is because i use the electric fan and water pump a lot in the summer to keep the engine temp down, at the track. the arizona summers are brutal especially at the race track.
yes, I have a on/off disconnect. I guess my real confusion here is with the 1 wire alternator. Right now it is running to the silenoid in the engine bay. I had it at one time (just trying stuff) ran to the battery in the trunk, well all that did was cause the alternator to get real hot just sitting there(not running). So, just leave it on the silenoid...right???? well, here is my other confusion........I know this is old school, but, I have always been told that one way to check if you alternator is good is to start the car and disconnect the battery, if the alternator is working, the car will continue to run......right? OK, here is the problem......My alternator on the silenoid is "after" the on/off disconnect, so I start the car....disconnect the battery and the car stays running....which makes the on/off switch useless. and makes me illegal at the track. I have not got something right and I am trying to figure out what????? Thanks again.
What are the intentions of the dual battery setup. 1. Do you want the power to be drawn from both batteries at the same time (double amperage) 2. Do you want one battery to function as a starting battery and the other to run accessories 3. Do you want everything to run from one battery and the second to function as a backup
I would think that if you ran the alt wire to the 'disconnect' side of the solenoid (if you know what I mean) then it should work. Have you tried relocating the alt wire to the opposite side of the solenoid? I also think you'd want to have an in-line fuse link ("Maxi-Fuse" or similar) with a fuse rated at the amperage of your alternator (or slightly below). The reason I'm interested in this is because I am curently in the middle of doing a similar set-up, only my alt isn't the one-wire type and I'm only using one battery (with a Flaming River Quick-Disconnect). I'm going today to get some #6 wire and 100 amp in-line fuse link for my alt. BTW, I'm only relaying information that I've recently been instructed to do. I am by no means, a pro at electrical. In fact, this wiring stuff is very intimidating to me. I've got a ton of MSD electronics and I just know I'm gonna fry them AND the EEC if I go it alone. Good luck (to us both)
Ok, the 2 batteries was really just a curiosity question. The running of the 1 wire....thats were the help is needed. Thanks,John.
Painless Performance sells a charging system shutdown relay kit as well as a high amp alternator shut down relay that will fix your disconnect issue.
run a 10 gage wire from the alternator to either of the "+" ... You need to size the alternator output wire according to the current capability of the alternator and how long the wire is. As for overcurrent protection, you can use a fuseable link, which is just a wire that's sized approximately two wire guages too small, or you can get a circuit breaker. With a circuit breaker you can run the full size wire required or larger to minimze voltage drop. So, how much current can your alternator supply and how long does the wire need to be? http://users.bestweb.net/~tomh/Car/Current%20Capacity.html
I am upping the output of the alternator to 100 amp. It is right now 60 amp. And as far as length goes.....to the back of the car. I figure around 14 feet or so?????
Wire calculations - see link http://www.powerstream.com/Wire_Size.htm I would twist together a double 10 gauge wire. If you have to be concerned about voltage drop over 20 feet or so in a chassis application - you need to go to a bigger wire. Cleaver
